AD Issued for Various Piper Models’ Rudder Post

The FAA has issued a new Airworthiness Directive (AD) for certain models of Piper aircraft which are not equipped with a rudder having a chromoly rudder post.

This AD was prompted by reports of two non-fatal accidents (PA-12, PA-14) that were caused by broken rudder posts that structurally failed above the upper hinge in flight. The National Transportation Safety Board (NTSB) published the report Structural Failure of Piper Part Number 40622 Rudder Posts Made of 1025 Carbon Steel (NTSB/AIR-22-02, January 2022) investigating these two accidents.

Before 1974, all rudders installed on Piper aircraft were equipped with 1025 carbon steel rudder posts. Starting in 1974, the rudder posts were manufactured from 4130N low-alloy steel (chromoly). The NTSB determined that the broken rudder posts resulted from the combination of fatigue loading and corrosion affecting the rudder assemblies made from 1025 carbon steel. The NTSB report included Safety Recommendation A-22-3 to the FAA to issue an AD requiring the replacement of rudders equipped with 1025 carbon steel rudder posts with rudders equipped with chromoly rudder posts.

This AD does not include PA-25 (Pawnee) or PA-36 (Pawnee Brave) models in its effectivity, however, NTSB provided comment on this AD when it was proposed, urging FAA to include PA-25 model aircraft in its effectivity, stating that it is likely affected by the same issue. FAA did not include the PA-25 in the final AD because the PA-25 type certificate was sold to a company in Argentina (Latinoamericana de Aviación S.A.). FAA plans to work with Argentina’s civil aviation authority to ensure this issue is addressed with the PA-25.

To Pawnee operators reading this, now is the time to check to ensure your rudder is equipped with a chromoly rudder post. Piper Service Bulletin 1379B (May 2024) specifies a procedure to determine if it is affected.

AD 2025-02-11 is effective March 20, 2025.